Motivation and emotion/Book/2014/Emotion paradox

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Emotion paradox:
What is the emotion paradox and
how does the conceptual act model explain emotion?

Overview[edit | edit source]

Figure 1. Facial expressions of seven universal emotions. The conceptual act model of emotion has challenged whether universal emotions exist.

You come home, hungry after a long day, walk into the kitchen and open the fridge to discover that the curry you had left for your dinner has gone. You are sure that your housemate has eaten it — this is not the first time he has taken your food from the fridge. You feel yourself getting hot, your grip on the fridge door tightens, and the vein in your forehead starts throbbing the way it always does when you are angry. You shut the fridge and stomp down the hallway ready to confront your housemate. You know you are angry and he will too when he sees you.

We believe that specific emotions, such as anger, fear, surprise, disgust, happiness, and sadness exist because we experience them. We also believe they exist because we see other people experience those emotions. However, scientists are yet to find a conclusive empirical base for the existence of emotions as discrete units (Barrett 2006a). This presents what Barrett (2006b) has referred to as the emotion paradox: a fundamental inconsistency between what we believe we know about emotion from our experiences and the lack of empirical evidence to support this belief.

This chapter will introduce the emotion paradox and the conceptual act model of emotion which has been proposed to rectify this paradox. In particular, this chapter will address the following questions:

  • What does the emotion paradox mean for our understanding of emotion?
  • What is the conceptual act model of emotion and how does it explain emotion?
  • How does the conceptual act model compare with other theories of emotion?
  • What are the main criticisms of the conceptual act model of emotion?
  • How can the conceptual act model of emotion be applied to understand and improve our emotional lives?

In reading this chapter you will learn more about an area of psychological inquiry which has the potential to fundamentally shift our understanding of emotion. You will discover how the conceptual act model of emotion can be applied to increase our understanding of how emotion works. You will also be introduced to some of the possible practical applications of the conceptual act model of emotion which have the potential to improve our emotional lives.

The emotion paradox[edit | edit source]

In the scenario described you know that you are angry. You also expect that your housemate will be able to tell you are angry when he hears you stomping down the hallway and sees you approaching him. However, if a scientist was observing this episode unfolding and wanted to assess your emotional state, studies suggest that there is no single measurement, or set of measurements, that a scientist could use to robustly identify that you are in a state of anger (Barrett, 2006b). By measuring your physiological and behavioural response, such as your rising heart-rate and your approach to your housemate, a scientist could take measurements of your affect and levels of threat or challenge (Barrett, 2006b). However, a scientist would not be able to objectively measure the emotion you are feeling, as signature bio-behavourial responses for specific emotions are yet to be reliably identified (Barrett, 2006b). The best way for the scientist to measure your emotion would be by asking you – verbal report, although flawed, is the most reliable measure of emotion experience (Barrett, 2006b).

The “emotion paradox” was introduced by psychologist Lisa Feldman Barrett in an article published in Personality and Social Psychology Review in 2006. The paradox, as proposed by Barrett, was that, although we are compelled by our experiences to believe that emotions are discrete events that can be recognised, science has yet to produce a clear set of criteria which indicate when an emotion is present and when it is not (Barrett, 2006b).

Similar to the belief held by humans that the sun revolved around the earth which was based on how the sun appeared when viewed from earth, the prevailing view of emotion (what Barrett refers to as the natural kind model) assumes that emotions have a universal signature and set of responses, even though this does not account for the majority of the data (Barrett, 2012). People’s belief that emotions are discrete and recognisable events is demonstrated in the way that people explain and categorise emotion. For example, people use emotion words including fear, anger, sadness and happiness to sort emotions into discrete categories and to describe their feelings and the feelings of others. People also assume that emotions “happen to” people, have set characteristics and are naturally occurring (Barrett, 2006b).

However, Barrett (2006b) suggests that the empirical basis for the assumption that emotions are discrete and recognisable entities is far from conclusive. In particular, gaps in the evidence about how emotion can be identified, measured, and described could suggest alternative explanations for the way emotion works. Some examples are detailed below:

Figure 2. What emotion is this man feeling? See Figure 5 for the answer. The conceptual act model of emotion suggests that contextual information assists us to diagnose emotions in others. author: Adam Kliczek, (CC-BY-SA-3.0.

Identifying and measuring emotion[edit | edit source]

The dominant understanding of emotion presumes that emotions produce behavioural and physiological response patterns including changes to feelings, bodily arousal, social expressions (including facial expressions, voice and social communication), and sense of purpose (Barrett, 2006b). Although some studies have identified some correlations between some response patterns and specific emotions (e.g., Ekman, Levenson, & Friesen, 1983; Levenson, Ekman, & Friesen, 1990), meta-analyses have not found distinct relationships between peripheral nervous system responses and each of the basic emotions (Cacioppo, Berntson, Larsen, Poehlmann, & Ito, 2000). However, specific peripheral nervous system responses for positive and negative affect have been identified (Cacioppa et al., 2000) as well as peripheral nervous system responses for threat and challenge (Quigley, Barrett, & Weinstein, 2002).

Correlations between facial expressions and emotions have been commonly highlighted as evidence of the existence of emotions as discrete entities (Barrett, 2006b). One such case is the famous experiment in which members of a preliterate Papua New Guinean tribe were able to select emotional labels that fit facial expressions (Ekman & Friesen, 1971). While Barrett (2006b) acknowledges that participants in studies matching facial expressions and emotions are able to assign emotion categories to posed facial expressions relatively reliably, she suggests that these results may be due to the way these studies are designed. This observation has also been made by other researchers (e.g., Russell, 2004). But when it comes to instrumental measurement of facial expressions, electromyography measurements, which record the electrical activity produced by facial muscles, are only able to determine positive or negative affect but not discrete emotion categories (Cacioppo et al., 2000).

Barrett (2006b) suggests that behavioural responses correspond to particular situational demands, rather than as a response to specific emotions, noting the range of behaviours that occur in response to specific emotions. Meta-analyses of neuro-imaging studies have failed to find specific neural correlates for anger, sadness, disgust and happiness (Barrett & Wager, 2006). Although specific behaviours may depend on specific neural structures, this does not necessarily mean that they are necessarily associated with particular emotion categories (Barrett, 2006b).

No distinct signatures for emotions have been identified across multiple studies. Variability is the norm – for example, one instance of happiness can look very different from another instance of happiness (Barrett, 2012).

Emotional granularity[edit | edit source]

Figure 3. Valence–arousal circumplex chart

Emotional granularity refers to the extent to which individuals discriminate between different emotion categories (Barrett, 2006b). People differ in emotional granularity: people who are low in emotional granularity characterise their emotional experiences in global terms, often focussed on pleasure-displeasure spectrum (known as valence), whereas people who are high in emotional granularity use more precise categorical distinctions to describe their emotions (Barrett, 2006b). Barrett (2006b) has suggested that the fact that people differ in the extent to which they differentiate between emotion categories is potential evidence that discrete emotion categories do not exist. An example of emotional granularity would be in the case of a person finding out they had received an unexpected windfall of money, someone who is low in emotional granularity may describe their feelings as “really good” whereas someone higher in emotional granularity may describe their feelings as “at first, I felt surprised and then I felt elated” indicating an ability to differentiate between changes in the emotional experience and to describe their emotional experience with a greater level of detail. That one person describes an experience as feeling "really good" whereas another describes it as "elation" calls into question the validity of specific emotion categories and suggests that an ability to differentiate between valence may be more universal than an ability to differentiate between specific emotions.

Self-reported experience[edit | edit source]

When people describe their emotional experience at least two properties are consistent: valence (pleasure-displeasure) and arousal (activation – deactivation) (Barrett, 2006b). An individual’s ability to discriminate between emotion categories is informed by their valence focus, which refers to their ability to differentiate between positive and negative emotions and arousal focus, which refers to an individual’s ability to discriminate between high and low arousal emotions (Barrett, 2006b). Valence focus is a universal ability, however, arousal focus is an ability that most, but not all, people have (Barrett, 2006b). As illustrated in Figure 3, when self-reports of emotional experience are recorded the collected data forms a circumplex shape of valence-arousal states. The circumplex shape that is formed when self-reports of emotional experience are measured is taken by Barrett (2006b) as a suggestion that specific emotion categories may not be qualitatively and categorically distinct.

The available evidence suggests that we can more reliably measure states of valence (pleasure - displeasure) and arousal (activation - deactivation) as part of the emotional experience than specific emotion categories. The fact that the available evidence has not been able to show that specific brain circuits for specific emotions exist does not mean that emotions do not exist, but means we need a better explanation for them (Barrett, 2012).

The conceptual act model and how it explains emotion[edit | edit source]

Barrett (2006b) proposes two possible resolutions to the emotion paradox: either better research is required to find the blueprint for each emotion, or an argument can be made that emotions are not biologically given but are constructed by categorisation. In line with the second option, Barrett (2006b) proposed the conceptual act model of emotion, referred to as the conceptual act theory in a later publication(Barrett, 2014a).

The conceptual act model of emotion hypothesises that emotion occurs when physical changes in the natural world (both physical changes in an individual’s own body and sensory changes from the world around them) are categorised by an individual using the conceptual knowledge that they have about emotion (Barrett, 2014a). It proposes that emotions are conceptual categories constructed from the combination of incoming sensory input with learned knowledge from the conceptual system (Barrett, 2014a). The model proposes that our experience of emotion works similarly to our experience of colour – in the same way that we use category knowledge about colour to shape perceptions of wavelengths of light into experience of colour, people use their knowledge of categories of emotion to inform their experience of emotion (Barrett, 2006b). The central propositions of the conceptual act model of emotion are:

  • emotions are conceptual categories and there is variation within each emotion category;
  • each occurrence of an emotion is constructed by the brain’s functional architecture — there can be some similarities between occurrences of emotions from different emotion categories;
  • emotional episodes emerge from the interaction of the systems that produce core affect and conceptual knowledge, they cannot be deconstructed and the workings of each system must be studied holistically – brain, body and surrounding context; and
  • emotional episodes have features that physical states alone do not have (i.e. an emotional experience is more than a physical experience alone; Barrett, 2014a).
The conceptual act model of emotion proposes that emotions are conceptual categories produced from the combination of core affect and conceptual knowledge.

Emotion = Core Affect (Valence + Arousal) + Conceptual Knowledge

Affective system[edit | edit source]

Before reading on, take a moment to answer the question "how you are feeling?"

To answer to this question, you likely would have momentarily consciously turned your attention to your internal state before words came to mind that you considered effectively described that state. For example, you might say you are sleepy, relaxed or excited.

Core affect can be imagined as a constantly flowing stream of information being collected by your brain providing information about the relationship between you and the world (Russell, 2003). At any time this core affect is consciously accessible (Russell, 2003). There are two dimensions of core affect which combine to produce the affective feeling that leads to emotion:

  • Valence (pleasure ↔ displeasure). This is a person's assessment of their current situation along a continuum of pleasure through to displeasure.
  • Arousal (activation ↔ deactivation). This is a person's feeling of mobilisation and energy along a continuum of activation to deactivation (Barrett, 2006b).

For example, if a person out camping crawled into their sleeping bag and then discovered a large spider was inside the sleeping bag, their core affect may be characterised by a valence state of displeasure (they were not pleased to find the spider in their sleeping bag) and an arousal state of activation (they felt like getting out of the sleeping bag as fast as they could). The emotional experiences the individual may report in that scenario would be expected to be those in the upper left quarter of the valence-arousal circumplex chart (Figure 3), such as reporting feeling afraid or alarmed.

The affective system:

  • is a primitive system in which states of the body are experienced as pleasant or unpleasant with some element of arousal;
  • forms the basis of all emotional states and is created from sensory information that is received in the brain;
  • can be clearly measured in the body and face;
  • is a fundamental feature of consciousness, and when foregrounded in consciousness it is experienced as an individual's reaction to the world; and
  • is species-general and can be found in all mammalian brains, especially in primates (Barrett, 2012).
Figure 3. The affective system is species-general, common to all mammals.
Two Way Arrow.jpg

Conceptual system[edit | edit source]

When considering the question "how you are feeling?" you would have instantaneously consciously assessed your affective state and automatically categorised that affective state by applying unconscious knowledge about emotion (Barrett, 2006b).

Situated conceptualisation is the instantaneous, ongoing, obligatory and automatic act in which conceptual knowledge is enactive and prepares the individual for action (Barrett, 2014a).

The process of situated conceptualisation involves the application of:

  • contextual information, including sensory, motor, and neuromuscularskeletal information. This can include the body's physical reaction to an affective state and what an individual sees or hears in the environment that influences the way they interpret an affective state;
  • language, this can include an individual's available emotional vocabulary to describe an affective state and is also influenced by an individual's level of emotional granularity;
  • culture, this can include cultural display rules of emotion and culturally-specific emotions; and
  • previous experience this can include an individual's previous experiences in categorising an affective state in a particular way and observations they have made of others, which reach forward to inform this experience of categorising an affective state (Barrett, 2006b).

The conceptual system:

  • involves rich, content-specific concepts for emotion categories that people use to categorise affective changes that they see in themselves and others, across the many different instances of an emotion;
  • is tailored to the immediate situation, acquired from prior experience and supported by language; and
  • is uniquely human (although it may exist in a limited form in great apes)(Barrett, 2012).
Figure 4. The conceptual system is species-specific, it is a uniquely human system.

The conceptual act model of emotion would explain the scenario in the kitchen in the following way: as you see the missing food your core affect becomes characterised by displeasure on the range of valence, you are not pleased to see your food is missing, and activation on the range of arousal, you are energised to confront your housemate about it. This core affect combines with your conceptual knowledge, including memories of previous interactions with your housemate; how your body feels when your vein throbs and your heart rate rises; how you have seen others react in these kinds of situations; and the words from the English language that you associate with how you are feeling. Your internal state of displeasure and activation, combined with your situated conceptualisation through applying your conceptual knowledge, leads to the experience which you call “anger.”

Empirical support for the conceptual act model of emotion[edit | edit source]

Research on the universality of facial expressions[edit | edit source]

Figure 5. A woman from the Himba tribe of Namibia. Research with people from the Himba tribe suggests emotion recognition may not be universal.

Studies which have shown that people from different cultures can identify a set of basic emotions have been taken as evidence that basic emotions are universal and discrete (e.g. Ekman & Friesen, 1971). However, recent research by Gendron, Robertson, van der Vyver, and Barrett (2014) has called into question these findings. An experiment involving participants from the US and participants from the Himba ethnic group from Namibia required participants to sort images of posed facial expressions into piles by emotion type. The experiment involved both anchored sorting, the same approach as was used in the earlier experiments in which cues were given, and also free-sorting in which no cues from the experimenter were given. When cues for emotion concepts were not given, Himba participants did not demonstrate the universal recognition of emotion, whereas US participants did. When cues were given by the researcher, both groups’ sorting more closely replicated universal recognition of emotion, however, there was significant cultural variation. This finding presents preliminary empirical evidence that perception of emotion is not universal, but culturally and conceptually contingent (Gendron et al., 2014).

Research on fear[edit | edit source]

Research suggests that the specific emotion of fear can be produced through the interaction of core affect and conceptual knowledge, influenced through priming (Lindquist & Barrett, 2008). Linquist and Barrett (2008) conducted an experiment to test the hypothesis of the conceptual act model by applying it to the emotion of fear. In the study, participants were primed with conceptual knowledge of either fear, anger, or a neutral prime by being required to describe a photograph displaying typical mild fear, anger, or a neutral photograph. Music and imagined scenarios were then used to induce an unpleasant, high arousal or neutral state. After that, participants completed a questionnaire of their likelihood of undertaking risky behaviours which was used to measure their world-focussed fear. The study found that, as predicted, individuals primed with conceptual knowledge of fear interpreted the unpleasant core affect as evidence that the world was threatening. Participants primed with anger or a neutral prime did not. The authors proposed that this study provided initial evidence that world-focussed experience of fear could be produced by the interaction between core-affect and conceptual knowledge.

Comparing the conceptual act model and other theories of emotion[edit | edit source]

Although the conceptual act model of emotion proposes a new way of understanding what emotions are and how they are formed, it has both similarities and differences with other theories of emotion.

Discrete emotion theory[edit | edit source]

In common with discrete emotion theory, the conceptual act model takes an evolutionary view inspired by the work of Charles Darwin. Whereas discrete emotion theory proposes there is a set of biologically-determined emotions which are common to all people and that there is a specific neural mechanism for each emotion, the conceptual act model hypotheses that general, not specific, neural processes interact to produce emotional episodes (Barrett, 2014a). The conceptual act model also proposes that it is core affect, rather than specific emotions, that are produced by neurological mechanisms (Barrett, 2014a). The conceptual act model shares discrete emotion theory’s view that emotional episodes can contain actions that are common across all species, for example,the fight or flight response. However, unlike discrete emotion theory, the conceptual act model does not predict that there is one-to-one mapping between these behavioural adaptations and specific categories of emotion (Barrett, 2014a). The conceptual act model also proposes that language and abstract emotion concepts are necessary for emotion to occur and that emotion does not occur in animals or non-verbal infants (Barrett, 2014a).

Appraisal theory[edit | edit source]

In common with the appraisal theory of emotion, the conceptual act model sees the formation of emotions as an act of meaning-making, suggesting emotions are produced when individuals make sense of the input from the world around and within them (Barrett, 2014a). Whereas causal appraisal models understand appraisals as mental processes that cause emotions, constituative appraisal models see appraisals as the way that affect is construed in a situation — a view which is more closely aligned with the conceptual act model of emotion (Barrett, 2014a).

Schachter and Singer theory[edit | edit source]

The conceptual act model has taken many influences from the Schachter and Singer theory of emotion, however, unlike the Schachter and Singer theory, the conceptual act model does not require the conscious experience of physiological arousal (Barrett, 2006b). It also does not require the cognitive influences on the feelings to be deliberate or produced by attribution (Barrett, 2006b). The cognitive processes of importance in the conceptual act model are those related to categorisation rather than making-meaning from the event (Barrett, 2006b).

Social constructivism[edit | edit source]

In common with social constructivist approaches to emotion which view emotions as cultural products of learned social rules, the conceptual act model of emotion sees emotions as context-specific and constructed from past experience (Barrett, 2014a). The conceptual act model views emotions as culturally-contingent performances which are created by the collective intentions of people (Barrett, 2014a). However, unlike social constructivism, the conceptual act model of emotion emphasises the interplay of biological processes and context.

Criticisms of the conceptual act model of emotion[edit | edit source]

The conceptual act model has been criticised by the proponents of basic emotion theories, Ekman (2014), Izard (2007), and Panksepp (2007). The main criticism of the conceptual act model of emotion is that it rejects that emotions exist as discrete and universal entities in the face of an established evidence base that suggests otherwise. Whereas Barrett called Ekman’s findings into question based on methodological flaws, Ekman has defended the original findings and the scores of subsequent studies that replicated the findings citing methodological limitations with Barrett’s approach (Ekman & Keltner, 2014). A second criticism is that Barrett has drawn on the literature selectively to support the model, conflating correlation and causation and overlooking findings that are not consistent with the conceptual act theory's hypotheses (Panksepp, 2007).

Although Barrett has adroitly rebutted criticisms posed by these theorists about her work, the fact remains that compelling evidence for the existence of universal, basic emotions has been collected and disemminated over many years. In cases where evidence that suggests a universal view of emotion exists, Barrett is often able to offer possible alternate explanations. For example, Barrett suggests that basic emotion facial expressions observed among congenitally blind people may be due to irregular muscle movements or contextual knowledge (Barrett, Lindquist, & Gendron, 2007). However, photographic evidence and large scale studies present convincing evidence which is difficult to discount, see, for example, Figure 6.

Practical applications of the conceptual act model of emotion[edit | edit source]

If sufficient empirical evidence is collected to support the propositions of the conceptual act model of emotion then this would discredit the prevailing understanding of emotions as discrete entities and mean that interventions developed based on that assumption would need to be repealed. For example, the Facial Action Coding System developed by Ekman has been applied to identify microexpressions in individuals which convey their intent. Systems based on Ekman’s theories have been implemented by the FBI, companies like Apple and US government agencies such as the Transport Security Administration. His approach has also influenced the way that patients with autism and schizophrenia are taught how to distinguish emotion using facial expression (Barrett, 2014b).

The conceptual act model of emotion has implications for how emotional intelligence in individuals is understood and developed. The model suggests that emotional granularity varies between people and that conceptualisation is a skill that can be taught (Barrett, 2006b). If correct, this could have applications for training in emotional intelligence, with wide-ranging applications to the workforce and beyond. Taking an approach where emotions are viewed as the product of the interaction between core affect and conceptual knowledge would also have practical implications for the practice of psychology. For example, rather than emotions being perceived as “happening to” an individual, if an individual has a sense of emotion as a conceptual act then there are practical implications for emotional regulation (Barrett, 2014a). This would offer individuals a greater sense of control over their emotional lives.

Conclusion[edit | edit source]

The conceptual act model of emotion has been proposed to address the emotion paradox, which states that although we believe that emotions are discrete entities because we experience them in ourselves and others, scientists are yet to find a conclusive empirical basis for the existence of emotions as discrete units (Barrett, 2006b). The conceptual act model of emotion proposes an alternative view of emotion, proposing that emotions are conceptual categories which are produced from the interplay of core affect and conceptual knowledge. There is an emerging body of empirical evidence to support this view, however, proponents of discrete emotion theory maintain that emotions are universal and discrete. The conceptual act model has attracted attention because it suggests a theoretical framework, and provides emerging empirical evidence, that could undermine the prevailing understanding of how human emotion works. If the evidence base for the conceptual act model continues to grow, there is the prospect that the conceptual act model, or a future refinement of the model, could be accepted as a legitimate alternative to the dominant understanding of emotion. This would mark a fundamental shift for psychological science and our understanding of the emotional lives of humans with wide-reaching practical applications to everyday life.

Figure 5. A football supporter expressing his happiness after a goal is shot, author: Adam Kliczek, (CC-BY-SA-3.0)

See also[edit | edit source]

References[edit | edit source]

Barrett, L. F., & Wager, T. (2006). The structure of emotion: Evidence from the neuroimaging of emotion. Current Directions in Psychological Science, 15, 79-85.

Barrett, L. F. (2006a). Emotions as natural kinds? Perspectives on Psychological Science, 1, 28-58.

Barrett, L. F. (2006b). Solving the emotion paradox: Categorization and the experience of emotion. Personality and Social Psychology Review, 10, 20-46.

Barrett, L. F., Lindquist, K., & Gendron, M. (2007). Language as a context for emotion perception. Trends in Cognitive Sciences, 11, 327-332.

Barrett, L. F. (2012). Measurements and conditions for happiness [Video file]. Retrieved from

Barrett, L. F. (2014a). The conceptual act theory: A précis. Emotion Review, 6, 292-297.

Barrett, L. F. (2014b, March 2). What faces can’t tell us. The New York Times. Retrieved from

Cacioppo, J. T., Berntson, G. G., Larsen, J. T., Poehlmann, K. M., & Ito, T. A. (2000). The psychophysiology of emotion. In R. Lewis & J. M. Haviland-Jones (Eds.) The handbook of emotion (2nd ed., pp. 173-191). New York: Guildford. Retrieved from

Ekman, P; Friesen, W (1971). "Constants across cultures in the face and emotion". Journal of Personality and Social Psychology, 17 (2): 124–9. doi:10.1037/h0030377.

Ekman, P., Levenson, R. W., & Friesen, W. V. (1983). Autonomic nervous system activity distinguishes among emotions. Science, 221(4616), 1208-1210.

Ekman P. & Keltner, D. (2014). Darwin’s claim of universals in facial expressions not challenged [Web log post]. Retrieved from

Gendron, M., Roberson, D., van der Vyver, J. M., & Barrett, L. F (2014). Perceptions of emotion from facial expressions are not culturally universal: Evidence from a remote culture. Emotion, 14, 251-262.

Izard, C. E. (2007). Basic emotions, natural kinds, emotion schemas, and a new paradigm. Perspectives on Psychological Science, 2 , 260-280.

Levenson, R. W., Ekman, P., & Friesen, W. V. (1990). Voluntary Facial Action Generates Emotion - Specific Automic Nervous System Activity. Psychophysiology, 27, 363-384.

Lindquist, K., & Barrett, L. F. (2008). Constructing emotion: The experience of fear as a conceptual act. Psychological Science, 19, 898-903.

Russell, J. A. (1994). Is there a universal recognition of emotion from facial expression? A review of the cross-cultural studies. Psychological Bulletin, 115, 102-141.

Russell, J. A. (2003). Core affect and the psychological construction of emotion. Psychological Review, 110, 145-172.

Panksepp, J. (2007). Neurologizing the psychology of affects: How appraisal-based constructivism and basic emotion theory can coexist. Perspectives in Psychological Science, 2, 281–296.

Quigley, K. S., Barrett, L. F., & Weinstein, S. (2002). Cardiovascular patterns associated with threat and challenge appraisals: Individual responses across time. Psychophysiology, 39, 1-11.

External links[edit | edit source]